I haven't hit with the RDiS 100 at all, so cannot speak to that. But I can definitely say that the RDiS 300 is more flexible than the 003 -- not by much, mind you; but it is more flexible and is also an easier racquet to swing.
Zheng Jie moved from the 003 to the RDiS 300; and indeed the two have specs that are very very similar. But having said that, I would order the RDiS 300 and play with it for a while, and if you like it still get two or three more. It's a great racquet that has not received the attention it deserves.